too much pump to finish workouts?

I get it when im not doing PH's too, I switch up my routine to back/bis same day and I can't get more than 3-4 sets on bi's because the pump is so hard I can't even curl my arms more than 1/2way up. I try to stretech them out and it is useless. It almost seems like this is impeeding my progress in my bi's. Any ideas on how to fix this or help it along?

its inevitable that you'll train the bis when performing back exercises. You could simply change your split around. Doing biceps with chest is very popular with many lifters, mainly for the same reason you mentioned. Cant go wrong with an arm day either.
Sage

u have the solution urself , either train it on a seperate day , or if u feel ure doing too much , dont work it at all ..
also , u might want to see how much u can minimise bicep involvement during pulling movements .

i have the same problem.. had that problem yesterdya.. im on m1t right now so its especially worse.. i cant do concentration curls anymore.. i was hurting on my 1st set.. i feel like im barely doing the exercise becuase im only getting it half up.. the pump is killer.. (which i like)

Might not work for you, but when I was having that same problem I tried changing angles- went with seated incline curls,etc. I could get enough sets in to exhaust my biceps and keep my arms and ego pumped.